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Copolycarbonate and transparent molded article obtained therefrom

a technology of molded articles and copolycarbonate, which is applied in the field of copolycarbonate and transparent molded articles obtained therefrom, can solve the problems of difficult molds, silver streaks, and low heat resistance, and achieve excellent heat resistance, flowability and transparency

Active Publication Date: 2015-04-28
TEIJIN LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0015]It is an object of the present invention to provide a copolycarbonate derived from a renewable resource and a transparent molded article obtained therefrom. It is another object of the present invention to provide a copolycarbonate which has excellent heat resistance, flowability and transparency and is prevented from undergoing a dimensional change by water absorption, coloring and producing a silver streak during molding.
[0042]A terpolycarbonate having a predetermined composition ratio and a specific terminal structure can be obtained by carrying out polymerization under the reaction conditions found by the present invention, thereby making it possible to obtain a copolycarbonate and a transparent molded article thereof which have a high plant ratio and also excellent heat resistance, flowability and transparency and are prevented from undergoing a dimensional change by water absorption and coloring and producing a silver streak during molding.

Problems solved by technology

However, it has recently been worried about the depletion of oil resources and desired to provide polycarbonates from raw materials obtained from biomass resources such as plants.
However, since a homopolycarbonate obtained from isosorbide has a rigid structure, its glass transition temperature and melt viscosity are extremely high, thereby making it difficult to mold it.
Since the thermal decomposition temperature of the isosorbide skeleton is low, when extrusion and molding are carried out at a temperature of 250° C. or higher, there occur problems such as coloration and the production of a silver streak.
Further, as isosorbide has high hygroscopic nature, a polycarbonate polymerized from isosorbide also has high hygroscopic nature, thereby causing a problem such as a dimensional change by water absorption when it is used for application in molded articles.
However, there is a trade-off relationship between the aliphatic diol and isosorbide, that is, when the amount of the aliphatic diol to be introduced is large, heat resistance degrades whereas when the amount of the aliphatic diol to be introduced is small, the great influence of the isosorbide skeleton appears and water absorption becomes high.
Therefore, it is difficult to use the above polycarbonate for application in a transparent molded article due to coloration and the production of a silver streak.
Even when these alicyclic diols are copolymerized, the obtained copolycarbonates are still unsatisfactory because they do not have high heat resistance and low water absorption at the same time like a polycarbonate obtained by copolymerizing an aliphatic diol (Patent Document 3).
However, the composition ratio and comonomers of the terpolycarbonate suitable for use in molded articles are not disclosed.

Method used

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  • Copolycarbonate and transparent molded article obtained therefrom
  • Copolycarbonate and transparent molded article obtained therefrom
  • Copolycarbonate and transparent molded article obtained therefrom

Examples

Experimental program
Comparison scheme
Effect test

example 1

(Heat Melting)

[0178]250.66 parts of isosorbide (to be abbreviated as ISS hereinafter), 274.18 parts of 2,2-bis(4-hydroxyphenyl)propane (to be abbreviated as BPA hereinafter), 60.84 parts of 1,6-hexanediol (to be abbreviated as HD hereinafter), 749.70 parts of diphenyl carbonate (to be abbreviated as DPC hereinafter), and 3.0×10−2 part of tetramethylammonium hydroxide and 1.0×10−4 part of sodium hydroxide as catalysts were heated at 170° C. in a nitrogen atmosphere to be molten.

(EI Reaction Step)

[0179]After it was confirmed that these substances were molten, an EI reaction step was started. After the start of depressurization, the pressure was reduced to a final level of 13.4 kPa over 70 minutes and maintained at that level after 13.4 kPa was reached. Concurrently with the start of depressurization, the temperature was raised at a rate of 10° C. / hr until the final resin temperature became 190° C. After 190° C. was reached, the resin was maintained at a pressure of 13.4 kPa and a temp...

example 2

[0186]The operation of Example 1 was repeated except that 315.83 parts of ISS, 242.85 parts of BPA, 24.34 parts of HD and 749.70 parts of DPC were used to measure the specific viscosity, glass transition temperature, 5% weight loss temperature and melt viscosity of the obtained pellet which are shown in Tables 1 and 2. The composition ratio and the terminal ratio were obtained in the same manner as in Example 1. A film was formed in the same manner as in Example 1 to measure its refractive index and Abbe's number which are shown in Table 2. A triple plate was injection molded in the same manner as in Example 1 to evaluate its color, appearance, saturation water absorption coefficient and residence stability.

example 3

[0187]The operation of Example 1 was repeated except that 330.87 parts of ISS, 242.85 parts of BPA, 12.17 parts of HD and 749.70 parts of DPC were used to measure the specific viscosity, glass transition temperature, 5% weight loss temperature and melt viscosity of the obtained pellet which are shown in Tables 1 and 2. The composition ratio and the terminal ratio were obtained in the same manner as in Example 1. A film was formed in the same manner as in Example 1 to measure its refractive index and Abbe's number which are shown in Table 2. A triple plate was injection molded in the same manner as in Example 1 to evaluate its color, appearance, saturation water absorption coefficient and residence stability.

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Abstract

A copolycarbonate that is derived from a renewable resource, is excellent in heat resistance, flowability and transparency, and prevented from undergoing a dimensional change by water absorption and coloring during molding as well as a transparent molded article obtained therefrom. The copolycarbonate contains predetermined amounts of a unit (A) constituted of an ether diol residue represented by the formula (1), a unit (B) constituted of a bisphenol residue represented by the formula (2), and a unit (C) constituted of another diol residue, wherein the ratio of terminal groups falls within the ranges of the expressions (i) and (ii).

Description

TECHNICAL FIELD[0001]The present invention relates to a copolycarbonate derived from a renewable resource and a transparent molded article obtained therefrom. More specifically, it relates to a copolycarbonate which has excellent heat resistance, flowability and transparency and is prevented from undergoing a dimensional change by water absorption and coloring during molding and a transparent molded article obtained therefrom.BACKGROUND ART[0002]Polycarbonates are generally produced by using raw materials derived from oil resources. However, it has recently been worried about the depletion of oil resources and desired to provide polycarbonates from raw materials obtained from biomass resources such as plants.[0003]Heretofore, studies have been made to obtain polycarbonates through transesterification with diphenyl carbonate by using isosorbide as a plant-derived monomer (for example, Non-patent Document 1, Non-patent Document 2 and Non-patent Document 3). However, since a homopolyca...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C08G64/00C08G63/02C08G64/12C08G64/16
CPCC08G64/1691C08G64/1608C08G64/12
Inventor TAKEDA, TSUYOSHIMOTOYOSHI, TETSUYAOKAMOTO, HIROSHI
Owner TEIJIN LTD